Proboscis Monkey

Fascinating facts about the Proboscis Monkey

• A male proboscis monkey's nose can grow to 10 centimetres long — so heavy it dangles over his mouth and gets in the way of eating. Scientists think the bigger the nose, the deeper his calls vibrate through the forest canopy, a sonic billboard that tells females he's a high-quality mate. Evolution didn't optimise for breathing; it optimised for being heard.
• Proboscis monkeys are the only primates that cannot digest ripe fruit. Their stomach is divided into chambers like a cow's, fermenting unripe seeds and leaves instead. A diet that would poison most mammals keeps them alive in Borneo's swamps, where they're competing with almost no one else for food — a trade-off that made them masters of a habitat nobody else wanted.
• They leap from tree to tree across Borneo's rivers by belly-flopping into the water first, then swimming to the next patch of forest with their semi-webbed feet. A 15-kilogram monkey can drop 15 metres into water without injury, absorbing the impact with a specialised spine and air sacs under their skin. They are the only monkeys on Earth built to dive.
• A proboscis monkey's gut microbiome is so different from other primates that scientists studying human digestion can't use them as models — they're that alien. A single individual is a walking fermentation chamber so specialised that transplanting their gut bacteria into a regular monkey would likely kill it. They've become a separate kingdom unto themselves.
• In the past 40 years, proboscis monkeys have lost 50 percent of their Borneo habitat to logging and palm oil plantations, shrinking from hundreds of thousands to fewer than 8,000 today. They cannot survive outside their swamp forests and will not cross open ground — trapped on an island in an island, watching their world burn. Their survival now depends entirely on protecting the mangroves they've lived in for millions of years.

At a glance

About the Proboscis Monkey

In the lush mangrove forests of Borneo, the proboscis monkey navigates its domain with a unique blend of elegance and clumsiness, its oversized nose leading the way as it crashes through the underbrush with a rustling of leaves and snapping of twigs. As it moves through the trees, its long, muscular arms propel it with a fluid grace, a testament to its remarkable adaptability in this fragile, endangered world. The proboscis monkey's very existence is a poignant reminder of the beauty and vulnerability of life in the wild, its fate inextricably linked to the preservation of its dwindling habitat.

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